Atorvastatin calcium loaded chitosan nanoparticles: in vitro evaluation and in vivo pharmacokinetic studies in rabbits

;In this study, we prepared atorvastatin calcium (AVST) loaded chitosan nanoparticles to improve the oral bioavailability of the drug. Nanoparticles were prepared by solvent evaporation technique and evaluated for its particle size, entrapment efficiency, zeta potential, ;in vitro; release and surface morphology by scanning electron microscopy (SEM). In addition, the pharmacokinetics of AVST from the optimized formulation (FT5) was compared with marketed immediate release formulation (Atorva;(r)); in rabbits. Particle size of prepared nanoparticles was ranged between 179.3 ± 7.12 to 256.8 ± 8.24 nm with a low polydispersity index (PI) value. Zeta potential study showed that the particles are stable with positive values between 13.03 ± 0.32 to 46.90 ± 0.49 mV. FT-IR studies confirmed the absence of incompatibility of AVST with excipient used in the formulations. ;In vitro; release study showed that the drug release was sustained for 48 h. Results of pharmacokinetics study showed significant changes in the pharmacokinetic parameter (2.2 fold increase in AUC) of the optimized formulation as compared to marketed formulation (Atorva;(r));. Thus, the developed nanoparticles evidenced the improvement of oral bioavailability of AVST in rabbit model.;;No presente estudo, preparamos nanopartículas de quitosana com atorvastatina cálcica (AVST) para melhorar a biodisponibilidade oral do fármaco. As nanopartículas foram preparadas pela técnica de evaporação de solvente, avaliando-se a granulometria, a eficiência de encapsulamento, o potencial zeta, a liberação ;in vitro;e a morfologia da superfície, por meio da microscopia eletrônica de varredura (MEV). Além disso, a farmacocinética da formulação otimizada de AVST (FT5) foi comparada com a formulação comercial, de liberação imediata, comercializada (Atorva(r)), em coelhos. O tamanho das das nanopartículas variou na faixa de 179,3 a 256,8 ± 7,12 ± 8,24 nm, com baixo índice polidispersibilidade (PI). O estudo do potencial Zeta mostrou que as partículas são estáveis, com valores positivos entre 13,03 ± 0,32 a 46,90 ± 0,49 mV. Os estudos de FT-IR confirmaram a ausência de incompatibilidade de AVST com o excipiente utilizado nas formulações. O estudo de liberação ;in vitro; mostrou que liberação sustentada do fármaco por 48 horas. Os resultados do estudo farmacocinético mostraram alterações significativas nos parâmetros (aumento de 2,2 vezes na ASC) da formulação otimizada em relação à comercializada (Atorva(r) ). Assim, o desenvolvimento de nanopartículas evidenciou a melhora da biodisponibilidade oral de AVST em coelhos.

FORMULATION AND IN-VITRO/EX-VIVO CHARACTERIZATIONS OF MICROEMULSION-BASED HYDROGEL FORMULATION OF ACECLOFENAC FOR TOPICAL APPLICATION

ABSTRACTObjectives: In this study, microemulsion-based hydrogel (MBH) formulation of aceclofenac was prepared for topical administration in the managementof pain and inflammation to overcome the gastrointestinal toxicity of the drug occurs with oral administration.Methods: The MBH formulation was prepared by two-step methods. In the first step, the drug loaded o/w microemulsion was prepared first bytitration method and in the second step; xanthan gum was added slowly to the microemulsion under homogenization to produce clear MBH. Thedeveloped MBH formulations were characterized by in-vitro evaluations, stability studies, and skin irritancy test. The ex-vivo permeation across ratepidermis using modified Keshary-Chien diffusion cell and anti-inflammatory activity of the selected MBH formulation was also evaluated in rat hindpaw edema model.Results: The developed MBH formulations showed good stability and acceptable physicochemical properties. The selected formulation (MBH2)showed the highest skin permeation rate (transdermal flux, 193.59±5.01 µg/cm/h; lag time, 0.80±0.01 h) and a maximum of 70.96% inhibition ofthe hind paw edema was measured after 8 h of the study.2Conclusion: Thus, the results obtained in this study suggest the feasibility of the MBH formulation of aceclofenac for topical application for thetreatment of pain and inflammation.Keywords: Aceclofenac, Microemulsion-based hydrogel, Transdermal flux, Ex-vivo permeation

PHYTOCHEMICAL SCREENING AND ANALGESIC EFFECTS OF ETHANOLIC EXTRACT OF PLANT MURDANIA NUDIFLORA (L) BRENAN (COMMELINACEAE) IN ALBINO MICE USING HOT PLATE METHOD

Objective: Murdania nudiflora (L) Brenan (Commelinaceae) has long been used in folk medicine in treatment of many diseases. In this study, attempts have been made for pharmacological screening of the plant Murdania nudiflora (L) Brenan (Commelinaceae) for analgesic activity and presence of different phytochemicals. Methods: To this end, ethanolic extract of Murdania nudiflora (L) Brenan (Commelinaceae) was evaluated for analgesic properties using plate reaction time in mice and phytochemical screening of the plant was done by different methods. Results: The analgesic study showed that the ethanolic extract of the leaves have significant analgesic effects (P < 0.05; P < 0.001) as compared to morphine sulphate (10 mg/kg) used as a standard drug. The result of the preliminary phytochemical studies revealed the presence of tannins, flavonoids, saponins, alkaloids as a whole and which are reported to be responsible for the analgesic and anti-inflammatory activities in many medicinal plants of this family. Conclusion: From these studies, it may be concluded that ethanol extracts of Murdania nudiflora (L) Brenan may contain novel bioactive principles with analgesic activity. Further study is required for evaluation of active principle(s) in different animal models

Methyl directed DNA mismatch repair in Vibrio cholerae

Mismatches in DNA occur either due to replication error or during recombination between homologous but non-identical DNA sequences or due to chemical modification of bases. The mismatch in DNA, if not repaired, result in high spontaneous mutation frequency. The repair has to be in the newly synthesized strand of the DNA molecule, otherwise the error will be fixed permanently. Three distinct mechanisms have been proposed for the repair of mismatches in DNA in prokaryotic cells and gene functions involved in these repair processes have been identified. The methyl-directed DNA mismatch repair has been examined inVibrio cholerae, a highly pathogenic gram negative bacterium and the causative agent of the diarrhoeal disease cholera. The DNA adenine methyltransferase encoding gene (dam) of this organism which is involved in strand discrimination during the repair process has been cloned and the complete nucleotide sequence has been determined.Vibrio cholerae dam gene codes for a 21.5 kDa protein and can substitute for theEscherichia coli enzyme. Overproduction ofVibrio cholerae Dam protein is neither hypermutable nor lethal both in Escherichia coli andVibrio cholerae. WhileEscherichia coli dam mutants are sensitive to 2-aminopurine,Vibrio cholerae 2-aminopurine sensitive mutants have been isolated with intact GATC methylation activity. The mutator genesmutS andmutL involved in the recognition of mismatch have been cloned, nucleotide sequence determined and their products characterized. Mutants ofmutS andmutL ofVibrio cholerae have been isolated and show high rate of spontaneous mutation frequency. ThemutU gene ofVibrio cholerae, the product of which is a DNA helicase II, codes for a 70 kDa protein. The deduced amino acid sequence of themutU gene hs all the consensus helicase motifs. The DNA cytosine methyltransferase encoding gene (dam) ofVibrio cholerae has also been cloned. Thedcm gene codes for a 53 kDa protein. This gene product might be involved in very short patch (VSP) repair of DNA mismatches. The vsr gene which is directly involved in VSP repair process codes for a 23 kDa protein. Using these information, the status of DNA mismatch repair inVibrio cholerae will be discussed

Atorvastatin calcium loaded chitosan nanoparticles: in vitro evaluation and in vivo pharmacokinetic studies in rabbits

In this study, we prepared atorvastatin calcium (AVST) loaded chitosan nanoparticles to improve the oral bioavailability of the drug. Nanoparticles were prepared by solvent evaporation technique and evaluated for its particle size, entrapment efficiency, zeta potential, in vitro release and surface morphology by scanning electron microscopy (SEM). In addition, the pharmacokinetics of AVST from the optimized formulation (FT5) was compared with marketed immediate release formulation (Atorva(r)) in rabbits. Particle size of prepared nanoparticles was ranged between 179.3 ± 7.12 to 256.8 ± 8.24 nm with a low polydispersity index (PI) value. Zeta potential study showed that the particles are stable with positive values between 13.03 ± 0.32 to 46.90 ± 0.49 mV. FT-IR studies confirmed the absence of incompatibility of AVST with excipient used in the formulations. In vitro release study showed that the drug release was sustained for 48 h. Results of pharmacokinetics study showed significant changes in the pharmacokinetic parameter (2.2 fold increase in AUC) of the optimized formulation as compared to marketed formulation (Atorva(r)). Thus, the developed nanoparticles evidenced the improvement of oral bioavailability of AVST in rabbit model.</p

A Mutation in the dam Gene of Vibrio-Cholerae - 2-Aminopurine Sensitivity with Intact Gatc Methylase Activity

Vibrio cholerae mutants sensitive to 2-aminopurine (2AP) but with DNA adenine methylase activity similar to parental cells have been isolated, The mutant strains were sensitive to ultraviolet light (UV), methyl methane sulphonate (MMS) and 9-aminoacridine. The spontaneous mutation frequency of the mutants were not significantly affected, Attempts to isolate dam- V, cholerae cells by screening 2AP sensitive cells have not been successful, All the mutant phenotypes could be suppressed by introducing the plasmid pRB103 carrying the dam gene of Escherichia coli into the mutant cells